KY Water Operator flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Safe yield

The maximum long-term pumping rate a well or wellfield can sustain without depleting storage, causing subsidence, or inducing intrusion of poorer-quality water.

Watershed delineation

Drawing the boundary of all land draining to an intake or well, using topographic contours and verified by dye tracing or flow monitoring where the surface divide is uncertain.

Wellhead protection area

The land surface around a well through which contaminants could reach the well, often divided into 1-year, 5-year, and 10-year time-of-travel zones for land-use control.

GWUDI

Groundwater under the direct influence of surface water; a dye trace or other evidence shows surface water reaches the well quickly, so full surface-water treatment rules apply.

MCL versus MCLG

The MCL is the enforceable maximum contaminant level; the MCLG is the non-enforceable health goal, often zero for carcinogens, set without considering treatment cost.

Treatment technique rule

A regulatory requirement specifying a required treatment method instead of a numeric MCL, used where contaminant monitoring at every sample point is impractical, such as turbidity limits.

Tier 1 public notice

Notice required within 24 hours for violations posing immediate health risk, such as an E. coli MCL violation or exceeding the nitrate MCL, delivered by broadcast and other means.

Consumer Confidence Report

Annual report due to customers by July 1 covering the prior year; it lists detected contaminants, MCLs, MCLGs, health effects, and source water information.

Locational running annual average

The running average of quarterly disinfection byproduct results calculated separately at each monitoring site, used to determine Stage 2 compliance for TTHM and HAA5.

Jar test purpose

A bench test that varies coagulant dose and pH under rapid and slow mixing to identify the dose producing the lowest settled and filtered turbidity.

Alum alkalinity consumption

Each mg/L of alum dosed consumes roughly 0.45 mg/L of alkalinity as CaCO3, so low-alkalinity waters may need lime or caustic to hold coagulation pH.

Velocity gradient G

A measure of mixing intensity in reciprocal seconds; rapid mix uses roughly 250-1000 per second briefly, while flocculation uses about 10-75 per second for 15-45 minutes.

Surface overflow rate

Filter or clarifier flow divided by its surface area, expressed in gpm/ft2; it sets the settling velocity a particle must exceed to be removed in a basin.

Media uniformity coefficient

The ratio of the 60th-percentile size (d60) to the effective size (d10) of filter media; a lower value means a more uniform bed and better backwash behavior.

Filter loading rate

Flow divided by filter surface area, typically 2-6 gpm/ft2 for rapid gravity filters; exceeding design rate raises effluent turbidity and shortens filter runs.

Combined filter effluent limit

Conventional and direct filtration systems must keep combined filter effluent turbidity at or below 0.3 NTU in at least 95% of monthly readings, with no reading above 1 NTU.

Backwash media expansion

Sand beds are expanded roughly 15-25% during backwash at about 20 C; colder water is denser and needs a higher backwash rate for the same expansion.

CT concept

The product of disinfectant residual concentration in mg/L and effective contact time in minutes, compared against the required CT for the target log inactivation.

Baffling factor

The ratio t10/T describing how much of a basin's theoretical detention time is actually credited, ranging from about 0.1 in unbaffled basins to 0.7 in well-baffled ones.

Chlorine species and pH

Hypochlorous acid dominates below about pH 6.5 and is far more biocidal than hypochlorite ion, which dominates above pH 8.5, so disinfection weakens at high pH.

Chloramination tradeoff

Chloramines form fewer regulated THMs and HAAs than free chlorine but require a free chlorine contact period first and nitrification monitoring in the distribution system.

Minimum distribution pressure

At least 20 psi must be maintained at ground level throughout the distribution system under all conditions, including during fire flow, to prevent contamination intrusion.

Hazen-Williams formula

hf = 10.44 * L * Q^1.852 / (C^1.852 * d^4.87) in US customary units, where C is the roughness coefficient, about 130-140 for new cement-lined ductile iron.

Unidirectional flushing

Flushing in the normal direction of flow at velocities of about 5 ft/s or more, with valves sequenced to isolate a main, to scour biofilm and sediment from the pipe.

Main disinfection per AWWA C651

New or repaired water mains are chlorinated, typically at 25 or 50 mg/L for 24 hours depending on method, flushed, and sampled before being placed in service.

Pump affinity laws

For a given pump, flow varies with speed, head with speed squared, and power with speed cubed, so a 10% speed reduction lowers power by about 27%.

Brake horsepower formula

BHP = (Q * TDH) / (3960 * pump efficiency), with Q in gpm and TDH in feet; dividing by motor efficiency gives wire-to-water power demand.

NPSH available

Atmospheric pressure head plus static suction head minus vapor pressure head minus suction friction losses; it must exceed NPSH required by a margin to prevent cavitation.

Backsiphonage versus backpressure

Backsiphonage results from negative pressure in the supply main; backpressure occurs when downstream pressure, such as from a boiler or pump, exceeds supply pressure.

Reduced pressure principle assembly

A testable backflow device with two check valves and a relief valve that protects against both backpressure and backsiphonage for high-hazard connections; tested at least annually.

Air gap separation

The highest-degree backflow protection: a physical gap of at least twice the effective pipe diameter, with a minimum of 1 inch, between the supply outlet and the flood rim.

Bacteriological holding time

Drinking water bacteriological samples must begin analysis within 30 hours of collection; they are collected in sterile thiosulfate-treated bottles from a flushed, clean tap.